Carrying a genetic risk for obesity and high blood pressure is associated with a shorter lifespan, a study suggests.
The study, “Trans-ethnic mega-biobank polygenic risk score analysis involving 676,000 individuals identified blood pressure and obesity as causal drivers affecting human longevity,” was presented at the 2019 annual meeting of the American Society of Human Genetics by Saori Sakaue, MD, its lead author from Osaka University in Japan.
“Meeting patients around the world, I’ve found that people want to understand their genetic risk,” Sakaue said in a press release. “When you find you are at a high risk for a disease, it is great to know your future health risk but obviously you cannot modify the inherited genetic risk. I wanted to find something that we could also modify to improve outcomes, such as lengthening lifespan, by utilizing the genetic data in a population scale.”
The analysis was based on polygenic risk scores (PRSs), a numerical indication of the risk for a given disease or trait based on a set of genetic variants. According to Sakaue, using genetic scores rather than clinical measurements makes it easier to find cause-and-effect associations.
“If you only look at raw clinical data associated to lifespan, you cannot show which attribute is cause and which is effect. For instance, when a patient is dying, their blood pressure is low, so you can’t necessarily know if blood pressure is the cause of their death,” she said.
“By using PRS,” she added, “we can get closer to identifying the cause, because PRS is less susceptible to the acquired confounding factors such as decline in general health.”
Results showed that PRSs associated with a higher risk for obesity or high blood pressure were significantly linked to a shorter lifespan in the combined data sets.
The link between genetic risk for obesity and shorter lifespan was stronger in the European groups, which could be due to the different genetic backgrounds of the populations in the data sets. This hypothesis is supported by epidemiological data, the scientists noted.
Overall, the data may contribute to the improvement of healthcare as the factors associated with a shortened lifespan can be targeted, the team said.
“Obesity and blood pressure can be modified through lifestyle changes and medications,” Sakaue said. “So, a clinician can tell his or her patients that genetics research suggests modifying these areas may help extend lifespan, in order to encourage their lifestyle changes.”
They now plan to collaborate with other biobanks to both increase genetic diversity and find more factors linked to lifespan.